It is known, in the field of watches, to use dials in the lower surface of which, i.e. on the movement side, are machined holes into which metal feet are driven. These metal feet serve, in particular, to hold the dials in place relative to the watch movement during assembly of the watch. This state of the art technique is disclosed, for example, in EP Patent No 0465988.
The making of such dials involves relatively complex machining operations, since the dials have to be pierced precisely several times before the metal feet are mounted. Further, the use of such dials in skeleton watches is unattractive.
Other devices for holding a watch dial exist and can at least partly overcome the aforementioned drawbacks.
U.S. Pat. No. 857,516, for example, discloses, in a particular embodiment, a polygonal-shaped mount into which the dial is forcibly inserted, under the effect of which the mount is deformed and the edges thereof hold the dial in place. The assembly formed by the dial and the mount is then disposed above the movement which includes a circular projecting wall for assembling the dial/mount assembly by snap fit.
This type of device for holding the dial on the watch movement is, however, unreliable over time. Indeed, the dial is held in place only by friction forces, so that shocks applied to the watch can cause a movement of the dial with respect to its reference position.
The device disclosed in U.S. Pat. No. 5,966,344 makes it possible to overcome this drawback. According to a first embodiment described in that patent document, a circular mount, fixed to the movement, includes, on the periphery thereof, recesses intended to receive, by force fit, corresponding portions of the dial. The force fit of the dial ensures that the latter cannot move, even as a result of shocks. However, this type of embodiment is unattractive in skeleton watches, since an opening can be seen between the dial and the mount. According to another embodiment disclosed by U.S. Pat. No. 5,966,344, the watch movement includes several holes arranged at the periphery thereof, the holes being intended to cooperate with feet integral with the dial. Such a device also involves complex machining operations, as the movement has to be pierced and the dial feet have to be made in one-piece with the dial.